It is known to connect paper, thin board or the like in an adhesive-free manner in such a way that two layers of paper or the like arranged on top of each other are deformed by means of a knurling roller out of the main plane of the layers. Thus, a certain denticulation of the two layers consisting of web sections or sheets is achieved. This kind of connection is not particularly firm. For this reason an adhesive is very often used in this context.
Lots of things are wrapped up in plastic sheets, which are glued or welded to one another or which are shrunk on. The use of plastic sheets is not desirable. Moreover, vapours result during the shrinking of sheets, which are not desirable, either. The wrapping up with paper necessitates the use of an adhesive, which on the one hand is not desirable for reasons of pollution control. Moreover, it takes a considerable time as a rule for the adhesive to cure or dry to such extent that the connecting seam is sufficiently firm. On the other hand, there are many fields of application where the demands on a firm packing or wrapping or the demands on a firm connection are not very high, since the packing or wrapping is provided for a short period of time as a rule for transport only.